BRITISH STANDARD
Gas pressure regulators for inlet pressures up to 100 bar
The European Standard EN 334:2005 has the status of a British Standard
ICS 23.060.40
BS EN 334:2005
BS EN 334:2005
National foreword This British Standard is the official English language version of EN 334:2005. It supersedes BS EN 334:1999 which will be withdrawn on 31 March 2008. The UK participation in its preparation was entrusted to Technical Committee GSE/32, Gas governors, which has the responsibility to: —
aid enquirers to understand the text;
—
present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed;
—
monitor related international and European developments and promulgate them in the UK.
A list of organizations represented on this committee can be obtained on request to its secretary. Warning The responsible BSI technical committee GSE/32 ‘Gas governors’ wishes to bring to the attention of users of this British Standard the following essential information. The UK as a member of CEN, is obliged to publish EN 334:2005 as a British Standard. However, attention is drawn to t he fact that during the development of this European Standard, the UK voted against its approval as a European Standard. The reason for this disapproval was that pressure regulators commonly used in the UK had been excluded from the harmonized part of the standard. As a result, the UK has applied for an extension of the date of with drawal of the existing BS EN 334:1999. This has been accepted. Hence BS EN 334:1999 will continue in existence in parallel with the 2005 version until March 2008. It is the intention of the BSI technical committee to have amendments to the harmonized standards approved by 2007 so that all devices are included in the harmonized part of the standard. At the present time gas pressure regulators are used in accordance with the UK national guidelines for pressure regulating stations up to 100 bar, issued by the Institute of Gas Engineers and Managers document, IGE/TD/13.
Summary of pages This document comprises a front cover, an inside front cover, page i, a blank page, the EN title page, pages 2 to 96, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.
This British Standard was published under the authority of the Standards Policy and Strategy Committee on 23 February 2006
© BSI 23 February 2006
ISBN 0 580 47837 8
Amendments issued since publication publication Amd. No.
Date
Comments
BS EN 334:2005
National foreword This British Standard is the official English language version of EN 334:2005. It supersedes BS EN 334:1999 which will be withdrawn on 31 March 2008. The UK participation in its preparation was entrusted to Technical Committee GSE/32, Gas governors, which has the responsibility to: —
aid enquirers to understand the text;
—
present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed;
—
monitor related international and European developments and promulgate them in the UK.
A list of organizations represented on this committee can be obtained on request to its secretary. Warning The responsible BSI technical committee GSE/32 ‘Gas governors’ wishes to bring to the attention of users of this British Standard the following essential information. The UK as a member of CEN, is obliged to publish EN 334:2005 as a British Standard. However, attention is drawn to t he fact that during the development of this European Standard, the UK voted against its approval as a European Standard. The reason for this disapproval was that pressure regulators commonly used in the UK had been excluded from the harmonized part of the standard. As a result, the UK has applied for an extension of the date of with drawal of the existing BS EN 334:1999. This has been accepted. Hence BS EN 334:1999 will continue in existence in parallel with the 2005 version until March 2008. It is the intention of the BSI technical committee to have amendments to the harmonized standards approved by 2007 so that all devices are included in the harmonized part of the standard. At the present time gas pressure regulators are used in accordance with the UK national guidelines for pressure regulating stations up to 100 bar, issued by the Institute of Gas Engineers and Managers document, IGE/TD/13.
Summary of pages This document comprises a front cover, an inside front cover, page i, a blank page, the EN title page, pages 2 to 96, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.
This British Standard was published under the authority of the Standards Policy and Strategy Committee on 23 February 2006
© BSI 23 February 2006
ISBN 0 580 47837 8
Amendments issued since publication publication Amd. No.
Date
Comments
BS EN 334:2005 Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI the BSI Catalogue under Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI the BSI Electronic Catalogue or Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.
i
blank
EUROPEAN STANDARD
EN 334
NORME EUROPÉENNE EUROPÄISCHE NORM
March 2005
ICS 23.060.40
Supersedes EN 334:1999
English version
Gas pressure regulators for inlet pressures up to 100 bar Appareils de régulation de pression de gaz (régulateurs) pour des pressions amont jusqu'à 100 bar
Gas-Druckregelgeräte für Eingangsdrücke bis 100 bar
This European Standard was approved by CEN on 23 December 2004. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the sam e status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36
© 2005 CEN
All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.
B-1050 Brussels
Ref. No. EN 334:2005: E
EN 334:2005 (E)
Contents page Foreword..............................................................................................................................................................5 1
Scope ......................................................................................................................................................6
2
Normative references ............................................................................................................................7
3 3.1 3.2 3.3 3.4
Terms, definitions and symbols...........................................................................................................8 Terms and definitions ...........................................................................................................................8 Control variables .................................................................................................................................13 Operating features in stable conditions............................................................................................15 Further functional terminology ..........................................................................................................19
4 4.1 4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 4.1.6 4.1.7 4.2 4.2.1 4.2.2 4.2.3 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.3.5 4.3.6
Construction requirements.................................................................................................................21 Basic requirements .............................................................................................................................21 General..................................................................................................................................................21 Gas pressure regulators with integrated safety devices.................................................................21 End connections..................................................................................................................................22 Flange ratings ......................................................................................................................................22 Nominal sizes and face-to-face dimensions .....................................................................................23 Sealing of the adjusting device..........................................................................................................26 Replacement of part affected by erosion or abrasion .....................................................................26 Materials ...............................................................................................................................................26 Requirements for metallic materials..................................................................................................26 Requirements for elastomers (including vulcanized rubbers) .......................................................31 Requirements for non metallic materials different from those in 4.2.2 .........................................31 Strength of housings...........................................................................................................................32 Body and its inner metallic partition walls........................................................................................32 Other pressure containing parts for integral strength pressure regulators .................................32 Other pressure containing parts for differential strength pressure regulators ............................32 Inner metallic partition walls ..............................................................................................................33 Minimum values of safety factor........................................................................................................33 Welded joint coefficient ......................................................................................................................33
5 5.1 5.1.1 5.1.2 5.2 5.2.1 5.2.2 5.2.3 5.3 5.3.1 5.3.2 5.3.3 5.4 5.5
Functional requirements.....................................................................................................................34 General..................................................................................................................................................34 Mounting position................................................................................................................................34 Sound emission ...................................................................................................................................34 Shell strength, external tightness and internal sealing...................................................................35 Shell strength.......................................................................................................................................35 External tightness ................................................................................................................................35 Internal sealing ....................................................................................................................................35 Control classifications ........................................................................................................................36 Accuracy under stable conditions.....................................................................................................36 Lock-up behaviour...............................................................................................................................36 Stable conditions.................................................................................................................................37 Final visual inspection ........................................................................................................................37 Fail-close conditions...........................................................................................................................37
6 6.1 6.2
Gas pressure regulator sizing............................................................................................................37 Flow behaviour ....................................................................................................................................37 Sizing equations for the calculation of volumetric flow rates of a gas pressure regulator with its control member in its mechanically fully open position....................................................38 Normal calculations .............................................................................................................................38
6.2.1
2
EN 334:2005 (E)
6.2.2 6.2.3 6.3 6.4 6.5 6.6
Practical calculations..........................................................................................................................38 Simplified calculations........................................................................................................................39 Calculation of the maximum accuracy flow rate..............................................................................39 Inherent flow characteristics..............................................................................................................39 Calculation of volumetric flow rates for partially open gas pressure regulators.........................40 Flow coefficient ...................................................................................................................................40
7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.7.1 7.7.2 7.7.3 7.7.4 7.7.5 7.7.6 7.7.7 7.7.8
Testing..................................................................................................................................................40 General .................................................................................................................................................40 Tests .....................................................................................................................................................40 Type test...............................................................................................................................................41 Selection of test samples ...................................................................................................................42 Routine tests........................................................................................................................................42 Production surveillance......................................................................................................................42 Test and verification methods ........................................................................................................... 42 Dimensional check and visual inspection ........................................................................................42 Materials check....................................................................................................................................42 Verification of the strength of pressure containing parts and inner metallic partition walls......43 Shell and inner metallic partition walls strength test ...................................................................... 44 Alternative shell and inner metallic partition walls strength test...................................................45 External tightness test........................................................................................................................45 Functional tests ...................................................................................................................................46 Final visual inspection........................................................................................................................58
8 8.1 8.1.1 8.1.2 8.2 8.2.1 8.2.2 8.3 8.3.1 8.3.2
Documentation ....................................................................................................................................58 Documentation related to type test ...................................................................................................58 Documentation required prior to type test .......................................................................................58 Test report............................................................................................................................................58 Documentation related to the routine tests......................................................................................58 Documentation provided at the request of the customer ............................................................... 58 Documentation provided with the regulator.....................................................................................59 Documentation related to production surveillance in accordance with 7.6..................................59 Documentation to be available for production surveillance...........................................................59 Production surveillance report .......................................................................................................... 59
9 9.1 9.2 9.3
Marking.................................................................................................................................................60 General requirements .........................................................................................................................60 Markings for the various connections ..............................................................................................61 Marking of integrated safety devices ................................................................................................ 61
Annex A (informative) Alternative methods for the determination of the accuracy class, the lockup pressure class, the maximum accuracy flow rate, the flow coefficients and the verification of the hysteresis band ....................................................................................................62 A.1 General .................................................................................................................................................62 A.2 Test methods .......................................................................................................................................62 A.2.1 Direct acting gas pressure regulator.................................................................................................62 A.2.2 Pilot controlled gas pressure regulators ..........................................................................................63 A.3 Determination of flow coefficients for larger capacity regulators ................................................. 64 Annex B (informative) Inspection certificate ................................................................................................70 Annex C (informative) Acceptance test ........................................................................................................ 72 )
Annex D (informative) Compliance evaluation ............................................................................................73 D.1 General .................................................................................................................................................73 D.2 Introduction..........................................................................................................................................73 D.3 Procedure.............................................................................................................................................73 D.4 Manufacturer’s compliance evaluation .............................................................................................74 D.5 Issue of the certificate of compliance ...............................................................................................74 Annex E (informative) Seat leakage .............................................................................................................. 75 Annex F (normative) Creep (venting) relief device ......................................................................................76 F.1 General .................................................................................................................................................76
3
EN 334:2005 (E)
F.2 F.3 F.3.1 F.3.2 F.4 F.5 F.6 F.7 F.8
Terms and definitions .........................................................................................................................76 Requirements.......................................................................................................................................76 Construction ........................................................................................................................................76 Functional requirements.....................................................................................................................76 Testing ..................................................................................................................................................76 Type test ...............................................................................................................................................77 Routine tests ........................................................................................................................................77 Documentation.....................................................................................................................................77 Marking .................................................................................................................................................77
Annex G (informative) Order specification ...................................................................................................78 G.1 General..................................................................................................................................................78 G.2 Minimum specifications......................................................................................................................78 G.2.1 Details of construction........................................................................................................................78 G.2.2 Dimensions...........................................................................................................................................78 G.2.3 Performance .........................................................................................................................................78 G.3 Optional specifications .......................................................................................................................79 Annex H (normative) Materials .......................................................................................................................80 H.1 Steel materials for pressure containing parts and inner metallic partition walls.........................80 H.2 Metallic materials different from steel materials for pressure containing parts and inner metallic partition walls ........................................................................................................................86 H.3 Materials for fixtures, integral process and sensing lines, connectors and fasteners................91 Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC ............................................................................................94 Bibliography......................................................................................................................................................95
4
EN 334:2005 (E)
Foreword This document (EN 334:2005) has been prepared by Technical Committee CEN/TC 235 “Gas pressure regulators and associated safety devices for use in gas transmission and distribution”, the secretariat of which is held by UNI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2005, and conflicting national standards shall be withdrawn at the latest by September 2005. This document supersedes EN 334:1999. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive 97/23/EC. For relationship with EU Directive 97/23/EC, see informative Annex ZA, which is an integral part of this document. Gas pressure regulators dealt with in this document are standard gas pressure regulators and, when used in pressure regulating stations complying with EN 12186 or EN 12279, they are considered as standard pressure equipment in accordance with Clause 3.1 of Art. 1 of Pressure Equipment Directive 97/23/EC (PED). For standard gas pressure regulators used in pressure regulating stations complying with EN 12186 or EN 12279, Table ZA.1 given in Annex ZA includes all applicable Essential Requirements given in Annex I of PED, except the external resistance to environmental conditions where corrosion occurs. The normative Annex H of this document lists some suitable materials for pressure containing parts, inner metallic partition walls, fasteners and connectors. Other materials may be used when complying with the restrictions given in Table 5. Gas pressure regulators complying with this document do not need protection against exceeding their allowable limit of pressure if the maximum downstream incidental pressure (MIP d) of the upstream gas pressure regulating station is less than or equal to 1,1 times the maximum allowable pressure (PS) of the regulator itself. The continuing integrity of gas pressure regulators is assured by periodic functional checks. For periodic functional checks it is common to refer to national regulations/standards where existing or users/manufacturers practices. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
5
EN 334:2005 (E)
1
Scope
This document specifies constructional and functional requirements, regulator sizing, testing, documentation and marking of gas pressure regulators used in the pressure regulating stations:
for inlet pressures up to 100 bar and nominal diameters up to DN 400;
for an operating temperature range from -20 °C to +60 °C,
which operate with fuel gases of the 1 st and 2nd family in accordance with EN 437 in transmission and distribution networks and also in commercial and industrial installations. "Gas pressure regulators" hereafter will be called "regulators" except in the titles. The harmonised part of this document deals with standard gas pressure regulators used in pressure regulating stations complying with EN 12186 or EN 12279. For gas pressure regulators integral strength type when used in pressure regulating stations complying with EN 12186 or EN 12279, Annex ZA lists all applicable Essential Requirements except the external resistance to environmental conditions where corrosion occurs. This document considers the following classes of regulators:
class 1: operating temperature range from -10 °C to 60 °C;
class 2: operating temperature range from -20 °C to 60 °C.
This document applies to regulators which use the pipeline gas as a source of control energy unassisted by any external power source. The regulator may incorporate a creep (venting) relief device, complying with the requirements in Annex F. The regulators complying with the requirements of this document may be declared as "in compliance with EN 334" and bear the marking “EN 334”. This document does not apply to:
regulators upstream from/on/in domestic gas-consuming appliances which are installed downstream of domestic gas meters;
regulators in accordance with prEN xxxxxx (WI 00235003 under preparation by CEN/TC 235);
regulators for which a specific document exists (e.g. EN 88, etc.);
industrial process control valves in accordance with EN 1349.
6
EN 334:2005 (E)
2
Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including amendments) applies. EN 287 (all parts), Qualification test of welders - Fusion welding . EN 288 (all parts), Specification and approval of welding procedures for metallic materials . EN 473, Non destructive testing – Qualification and certification of NDT personnel – General principles . EN 571-1, Non destructive testing – Penetrant testing – Part 1: General principles . EN 970, Non-destructive examination of fusion welds – Visual examination . EN 1289, Non-destructive examination of welds – Penetrant testing of welds – Acceptance levels . EN 1290, Non-destructive examination of welds – Magnetic particle examination of welds . EN 1291, Non-destructive examination of welds – Magnetic particle testing of welds – Acceptance levels . EN 1349, Industrial process control valves. EN 1418, Welding personnel – Approval testing of welding operators for fusion welding and resistance weld setters for fully mechanised and automatic welding of metallic materials . EN 1435, Non-destructive examination of welds – Radiographic examination of welded joints . EN 1712, Non-destructive examination of welds – Ultrasonic examination of welded joints – Acceptance levels . EN 1713, Non-destructive examination of welds – Ultrasonic examination – Characterization of indications in welds. EN 1714, Non- destructive examination of welds – Ultrasonic examination of welded joints . EN 10045-1, Metallic materials – Charpy impact test – Part 1: Test method . EN 10204, Metallic products – Types of inspection documents . EN 12186, Gas supply systems – Gas pressure regulating stations for transmission and distribution – Functional requirements. EN 12279, Gas supply systems – Gas pressure regulating installations on service lines – Functional requirements. EN 12517, Non-destructive examination of welds – Radiographic examination of welded joints – Acceptance levels. EN 12627, Industrial valves – Butt welding ends for steel valves . EN 13445-4, Unfired pressure vessels – Part 4: Fabrication. EN 14382, Safety devices for gas pressure regulating stations and installations – Gas safety shut-off devices for inlet pressures up to 100 bar .
7
EN 334:2005 (E)
EN 60534-1:1993, Industrial-process control valves – Part 1: Control valve terminology and general considerations (IEC 60534-1:1987). EN 60534-2-1, Industrial-process control valves – Part 2-1: Flow capacity – Sizing equations for fluid flow under installed conditions (IEC 60534-2-1:1998). EN 60534-2-3, Industrial-process control valves – Part 2-3: Flow capacity – Test procedures (IEC 60534-23:1997). EN ISO 175:2000, Plastics – Methods of test for the determination of the effects of immersion in liquid chemicals (ISO 175:1999). EN ISO/IEC 17025:2000, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:1999). ISO 7-1, Pipe threads where pressure tight joints are made on threads – Part 1: Dimensions, tolerances and designation. ISO 1817, Rubber, vulcanized – Determination of the effect of liquids . ISO 3419, Non-alloy and alloy steel butt-welding fittings . ISO 5752, Metal valves for use in flanged pipe systems – Face-to-face and centre-to-face dimensions . ISO 7005(all parts), Metallic flanges. ANSI/ASME B1.20.1:1983, Pipe threads, general purpose (inch). ASME B16.34:1996, Valves – Flanged, threaded and welding end . MSS SP 55:1985, Quality standard for steel castings for valves, flanges and fittings and other piping components (Visual method).
3
Terms, definitions and symbols
3.1 Terms and definitions For the purposes of this document, the terms and definitions given in EN 60534-1:1993 and the following apply. 3.1.1 gas pressure regulator device whose function is to maintain the value of the controlled variable (see 3.2.2.1) within its tolerance field irrespective of disturbance variables 3.1.1.1 direct acting gas pressure regulator regulator in which the net force required to move the control member is supplied directly by the controlled variable (see example in Figure 1)
8
EN 334:2005 (E)
Key 1
Setting element
6 Sensing line
2
Detector element
7 Regulator body
3
Breather/exhaust line
8 Valve seats
4
Actuator
9 Seat ring
5
Casing of actuator
10 Control member
1 + 2 = Controller
Figure 1 — Example of a direct acting regulator 3.1.1.2 pilot controlled gas pressure regulator (indirect acting) regulator in which the net force required to move the control member is supplied by a pilot (see example in Figure 2)
9
EN 334:2005 (E)
Key 1
Fixture
6 Regulator body
2
Pilot
7 Valve seats
3
Actuator
8 Seat ring
4
Casing of actuator
9 Control member
5
Sensing/process line
10 Motorization chamber
Figure 2 — Example of a pilot controlled regulator 3.1.1.3 monitor second regulator normally installed in series with an active regulator which has the task of maintaining the controlled variable within allowable limits in the event of its value exceeds a pre-established value (e.g. in the event of opening of the active regulator due to a failure, etc.) 3.1.1.4 series of regulators regulators with the same design concept but differing only in size 3.1.1.5 fail open regulator regulator whose control member automatically tends to open when the main diaphragm fails or when the energy required to move the control member fails NOTE
The definition in this clause is based on typical control failure modes.
3.1.1.6 fail close regulator regulator whose control member automatically tends to close when the main diaphragm fails or when the energy required to move the control member fails NOTE
The definition in this clause is based on typical control failure modes.
3.1.1.7 integral strength regulator regulator in which the pressure containing parts have a design pressure equal to the maximum allowable pressure PS
10
EN 334:2005 (E)
3.1.1.8 differential strength regulator regulator in which some of the pressure containing parts have a design pressure less than the maximum allowable pressure PS 3.1.1.9 regulator size nominal inlet diameter nominal size DN of the inlet connection in accordance with EN ISO 6708 3.1.1.10 nominal outlet diameter nominal size DN of the outlet connection in accordance with EN ISO 6708 3.1.2 main components parts including normally: control member, regulator body, actuator, casing of actuator, controller, pilot (only in pilot controlled regulators) NOTE The regulator might include additional devices such as a shut-off device, a monitor, a relief valve and other fixtures. The Figures 1 and 2 serve as examples.
3.1.2.1 control member movable part of the regulator which is positioned in the flow path to restrict the flow through the regulator NOTE
A control member may be a plug, ball, disk, vane, gate, diaphragm, etc.
3.1.2.2 body main pressure containing envelope which provides the fluid flow passageway and the pipe end connections 3.1.2.3 valve seats corresponding sealing surfaces within a regulator which make full contact only when the control member is in the closed position 3.1.2.4 seat ring part assembled in a component of the regulator to provide a replaceable seat 3.1.2.5 actuator device or mechanism which changes the signal from the controller into a corresponding movement controlling the position of the control member 3.1.2.6 casing of actuator housing of the actuator (which may consist of two chambers under pressure) NOTE When the pressure in each chamber is different from atmospheric pressure, the chamber at the higher pressure is termed the "motorization chamber".
3.1.2.7 controller device which normally includes:
a setting element, normally a spring, to obtain the set value of the controlled variable;
11
EN 334:2005 (E)
a detector element, normally a diaphragm, for the controlled variable
3.1.2.8 pilot device which includes:
a setting element to obtain the set value of the controlled variable;
a detector element for the controlled variable;
a unit which compares the set value of the controlled variable with its feedback value;
a system which provides the motorization energy for the actuator
3.1.2.9 main diaphragm diaphragm, the function of which is to detect the feedback of the controlled variable and/or the diaphragm which provides the thrust to move the control member 3.1.2.10 pressure containing parts parts whose failure to function would result in a release of the retained fuel gas to the atmosphere which include bodies, control member, bonnets, the casing of the actuator, blind flanges and pipes for process and sensing lines 3.1.2.11 inner metallic partition wall metallic wall that separates a chamber into two individual pressure-containing chambers at different pressures under normal operating conditions 3.1.3 accessories parts or minor devices connected to the regulator 3.1.3.1 process and sensing lines lines which connect impulse points to the regulator NOTE Sensing and process lines may be integrated into the regulator or external to the regulator. Those lines with no internal flow are termed "sensing lines"; those with internal flow are te rmed "process lines".
3.1.3.2 breather line connection line between the controller and/or pilot and atmosphere to equalize the pressure on the detector element when it changes its position in normal operating conditions NOTE
In the event of a fault in the detector element this line may become an exhaust line.
3.1.3.3 exhaust line connection line between the regulator or its fixtures and atmosphere for the safe exhausting of gas in the event of failure of any part 3.1.3.4 fixtures functional devices connected to the main components of the regulator (see 3.1.2)
12
EN 334:2005 (E)
3.2 Control variables 3.2.1
Reference values
3.2.1.1 pressure all pressures specified in this document are static gauge pressures NOTE
)
Pressure is expressed in bar 1 .
3.2.1.1.1 inlet pressure pu gas pressure at the inlet of the regulator 3.2.1.1.2 outlet pressure pd gas pressure at the outlet of the regulator 3.2.1.1.3 differential pressure ∆ p difference between two values of pressure at two different points 3.2.1.1.4 motorization pressure pm gas pressure in the motorization chamber 3.2.1.1.5 pilot feeding pressure pup gas pressure at the inlet of the pilot 3.2.1.2
Flow conditions
3.2.1.2.1 normal conditions absolute pressure pn of 1,013 bar and temperature T n of 0 °C (273,15 K) NOTE
For calculation purposes a value of 273 K is used in this document.
3.2.1.2.2 gas volume volume of gas at normal conditions NOTE
Gas volume is expressed in m3.
1) 1 bar = 1 000 mbar = 105 N/m2 = 105 Pa = 10-1 MPa.
13
EN 334:2005 (E)
3.2.1.2.3 volumetric flow rate Q v olume of gas which flows through the regulator in unit time, at normal conditions NOTE
Volumetric flow rate is expressed in m3/h.
3.2.1.3 sound pressure level LpA sound pressure frequency weightings A in accordance with EN 61672-1 3.2.2
Variables in the controlling process
3.2.2.1 controlled variable X variable which is monitored by the controlling process NOTE
In this document, only the outlet pressure "pd" is considered as the controlled variable.
3.2.2.2 disturbance variable Z variables acting from outside on the controlling process. In the case of regulators with the outlet pressure as the controlled variable, the disturbance variables are essentially:
fluctuations in the inlet pressure, pu;
changes in the volumetric flow rate, Q
3.2.3
Possible values of all variables
3.2.3.1 actual value instantaneous value of any variable at any instant. It is specified by the index "i" added to the symbol of the variable 3.2.3.2 maximum value highest value, which is specified by the subscript "max" added to the symbol of the variable:
to which any variable can be adjusted or to which it is limited;
any variable may reach during a series of measurements or during a certain time period
3.2.3.3 minimum value lowest value, which is specified by the index "min" added to the symbol of the variable:
to which any variable can be adjusted or to which it is limited;
any variable may reach during a series of measurements or during a certain time period
14
EN 334:2005 (E)
3.2.4
Terms pertinent to the controlled variable
3.2.4.1 set point pds nominal value of the controlled variable NOTE
The set point is not directly measurable but determined as shown in Figure 5.
3.2.4.2 set range W d whole range of set points which can be obtained from a regulator by adjustment and/or the replacement of some components (i.e. replacement of the valve seat or setting element e.g. spring) 3.2.4.3 specific set range W ds whole range of set points which can be obtained from a regulator by adjustment and with no replacement of its components 3.2.4.4 control deviation X W difference between the actual value of the controlled variable and the set point 3.2.4.5 regulation change control deviation, X W expressed as a percentage of the set point
3.3 Operating features in stable conditions 3.3.1 stable conditions conditions when the controlled variable settles to a stable value after a disturbance has occurred 3.3.2 performance curve graphic representation of the controlled variable as a function of the volumetric flow rate NOTE This curve is determined by increasing and then decreasing the volumetric flow rate with constant inlet pressure and set point (see Figure 3).
3.3.3 hysteresis band difference between the two values of outlet pressure for a given volumetric flow rate (see Figure 3)
15
EN 334:2005 (E)
Key 1
Max hysteresis band
2
Hysteresis band Start setting Measured values
Figure 3 — Performance curve ( pds constant, pu constant)
Figure 4 — Family of performance curves ( pds constant) 3.3.4 family of performance curves set of the performance curves for each value of inlet pressure determined for a given set point (see Figure 4)
16
EN 334:2005 (E)
3.3.5
Features pertinent to accuracy
3.3.5.1 accuracy average, expressed as a percentage of the set point, of the absolute maximum values of the positive and negative control deviation within the operating range 3.3.5.2 accuracy class AC maximum permissible value of the accuracy 3.3.5.3 inlet pressure range bpu range of the inlet pressure for which the regulator ensures a given accuracy class NOTE
The inlet pressure range is characterized by its limit values pumax and pumin.
3.3.5.4 maximum accuracy flow rate lowest value of the maximum volumetric flow rate up to which, for a given set point and within the ambient temperature range specified, a given accuracy class is ensured:
at the lowest inlet pressure (see Figure 5)
Qmax,pumin ;
at the highest inlet pressure (see Figure 5)
Qmax,pumax ;
at an intermediate inlet pressure between pumax and pumin (see Figure 5)
Qmax,pu
3.3.6
Features pertinent to lock-up behaviour
3.3.6.1 lock-up time t f time taken for the control member to move from an open position to the closed position
17
EN 334:2005 (E)
= Qmax with the control member at the limit imposed by the mechanical stop
Figure 5 — Family of performance curves indicating maximum accuracy flow rates and minimum flow rates ( pds constant, stable conditions) 3.3.6.2 lock-up pressure pf pressure that occurs at the measuring point of the controlled variable when the control member is in the closed position NOTE The lock-up pressure corresponds to the outlet pressure at the volumetric flow rate Q = 0 in the performance curve (see Figure 3). It results when the time taken for a change in volumetric flow rate from Q to zero is greater than the lock- up time of the regulator.
3.3.6.3 lock-up pressure class SG maximum permissible positive difference between the actual lock-up pressure and the set point expressed as a percentage of the set point e.g. SG =
P f - P ds P ds
× 100
(1)
3.3.6.4 minimum flow rate largest value of the minimum volumetric flow rate down to which, for a given set point and within the ambient temperature range specified, stable conditions as per 5.3.3 are obtained:
at the lowest inlet pressure (see Figure 5)
Qmin,pumin;
at the highest inlet pressure (see Figure 5)
Qmin,pumax ;
at an intermediate inlet pressure between pumax and pumin (see Figure 5)
Qmin,pu
18
EN 334:2005 (E)
3.3.6.5 lock-up pressure zone zone between the volumetric flow rate Q = 0 and the minimum flow rate Qmin,pu for each corresponding inlet pressure and set point (see Figure 6) 3.3.6.6 class of lock-up pressure zone SZ maximum permissible lock-up pressure zone for specified:
inlet pressure pu or inlet pressure range bpu;
set point pds or specific set range W ds or set range W d;
which is expressed as the percentage of Qmin,pu to Qmax,pu, i.e. SZ =
Qmin, pu Qmax, pu
× 100
(2)
Key 1
Lock-up pressure zone
Figure 6 — Performance curve indicating lock-up pressure zone (stable condition)
3.4 3.4.1
Further functional terminology Pressures pertinent to design of gas pressure regulator
3.4.1.1 component operating pressure p gas pressure occurring in any part of a regulator during operation
19
EN 334:2005 (E)
3.4.1.2 maximum component operating pressure pmax highest operating pressure at which a component of a regulator will continuously operate within specified conditions 3.4.1.3 maximum allowable pressure PS maximum pressure for which the body and its inner metallic partition walls are designed in accordance with the strength requirements in this document 3.4.1.4 test pressure pressure applied to a section of the regulator for a limited period of time in order to prove certain characteristics 3.4.1.5 limit pressure pl pressure at which yielding becomes apparent in any component of the regulator or its fixtures 3.4.1.6 safety factor ratio of the limit pressure pl to the maximum allowable pressure PS applied to:
the regulator body: Sb;
the other pressure containing parts of the regulator: S
3.4.1.7 maximum inlet pressure pumax highest inlet pressure at which the regulator can continuously operate within specified conditions 3.4.1.8 permissible outlet pressure pdmax highest outlet pressure at which the regulator can continuously operate within specified conditions 3.4.1.9 minimum operating differential pressure ∆ pmin minimum operating differential pressure between the inlet and outlet pressures below which the regulator will no longer function correctly within specified conditions 3.4.2 nominal pressure numerical designation relating to pressure, which is a convenient round number for reference purposes in accordance with the relevant parts of ISO 7005 (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1) NOTE 1 For the specific purpose of this document this term applies to flanges.
20
EN 334:2005 (E)
EXAMPLE NOTE 2
PN 16. For strength of envelope see 3.4.1.3.
3.4.3 operating temperature range temperature range at which the regulator components and fixtures are capable of operating continuously
4
Construction requirements
4.1 Basic requirements 4.1.1
General
The main function of a regulator is to maintain the value of the controlled variable within its tolerance field irrespective of the disturbance variables. Regulators shall not have any continuous discharge of gas into the atmosphere, however, temporary discharges from fixtures may occur. Regulators shall be designed so that the external tightness and internal sealing shall meet the requirements of 5.2. If in the event of failure of the regulator (e.g. failure of a diaphragm) leakage is possible, a tapping connection of at least DN 10 for any breather line or device shall be provided. Pressure containing parts including measuring and test points, which may be dismantled for servicing, adjustment or conversion shall be made pressure tight by mechanical means (e.g. metal to metal joints, o-rings, gaskets, etc.). Jointing compounds, such as liquids and pastes, shall not be used. Jointing compounds, however, may be used for permanent assemblies and shall remain effective under normal operating conditions. Pressure containing parts not intended to be dismantled during servicing, adjustment or conversion shall be sealed by means which will show evidence of interference (e.g. lacquer). Any breather line or device fitted shall be designed to prevent the ingr ess of foreign materials. When external protrusions or other external parts need special care to cover the hazards during transport and handling, the manual shall include the provisions to cover these risks. The motorization energy in a pilot controlled regulator shall be provided by the gas upstream of the regulator. 4.1.2
Gas pressure regulators with integrated safety devices )
Additional integrated (sam e body) safety devices i.e. gas safety shut-off devices (SSD) 2 and/or a monitor and specific safety devices in accordance with 4.3.3 shall be functionally independent from the regulator. This requirement is met if the function of the regulator is not affected in the event of the failure of one or more of the following safety device components:
closure member;
seat ring;
2) For this subject see EN 14382 Safety devices for gas pressure regulating stations and installations - Gas safety shut-off
devices for operating pressures up to 100 bar .
21
EN 334:2005 (E)
actuator;
casing of actuator;
controller;
pilot;
sensing and process lines.
Further, when the integrated safety device utilizes pipeline gas as a source of energy for its operation this shall be taken from upstream of the regulator. When the integrated safety device is a slam shut device or a cut-off device or a monitor, the motorization energy for regulator when a piloted controlled type, shall be provided by the gas downstream from the safety device. 4.1.3
End connections
End connections may be one of the following:
flanged connections in accordance with the applicable parts of ISO 7005 (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, 1759-4 and EN 1759-1;
flangeless type (e.g. wafer body);
threaded connections in accordance with ISO 7-1 (this document shall be replaced when equivalent documents are available. At the time of writing some parts of this document are equivalent to EN 10226-1 and some other parts are under study in prEN 10226-2) or ANSI/ASME B1.20.1 (this document shall be replaced by the equivalent document when it is available. At the time of writing this subject is under study in prEN 10226-2) for:
DN ≤ 50;
DN ≤ 80 and PS ≤ 16 bar;
compression fittings for DN ≤ 50;
butt weld connections in accordance with EN 12627.
4.1.4
Flange ratings
The PN ratings for flanges shall be selected from the following designations: )
6 - 10 - 16 - 20 - 25 - 40 - 50 - 110 3
according to the relevant parts of ISO 7005 (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1). The underlined designations are preferred.
3 ) The nominal pressure designations PN 20, PN 50 and PN 110 are equivalent to class ratings 150, 300 and 600
respectively.
22
EN 334:2005 (E)
4.1.5
Nominal sizes and face-to-face dimensions
Regulators with flange connections should have the same nominal size at inlet and outlet. The nominal sizes and the face-to-face dimensions given in Table 1 are recommended. Alternatively, the nominal sizes and the face-to-face dim ensions may be taken from Table 2. Flangeless regulators (regulators that have no line flanges but are intended to be installed by clamping between pipes flanges) are permitted as an alternative. In this case regulators should have the same nominal size at inlet and outlet and face-to-face dimensions should be taken from Tables 3 or 4. The following regulators are permitted:
those with different nominal inlet and outlet sizes;
those with face-to-face dimensions differing from those given in Tables 1 and 2;
angle pattern bodies in accordance with ISO 5752.
23
EN 334:2005 (E)
Table 1 — Recommended face-to face dimensions for flanged regulators Nominal size DN
Nominal pressure PN 10/16/20 a
PN 25/40/50
PN 110
Face-to-face dimensions in mm 25
184
197
210
40
222
235
251
50
254
267
286
65
276 b
292 b
311 b
80
298
317
337
100
352
368
394
150
451
473
508
200
543
568
610
250
673
708
752
300
737
775
819
350
889
927
972
400
1016
1057
1108
Limit deviations for face-to-face dimensions in mm
±2
±3
Source: Tables 1 and 2 of EN 60534-3-1:2000 (nominal pressure in accordance with the relevant parts of ISO 7005 – some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1). a
In some countries the group PN 10/16/20 includes also PN 6.
b
Face-to-face dimensions according to Table 1 of IEC 60534-3.
Table 2 — Alternative face-to-face dimensions for flanged regulators Nominal size
Nominal pressure
Limit deviations for face-to-face dimensions in mm
DN PN 10/16/25/40/50 a
PN 110
Face-to-face dimensions in mm 25
160
230
40
200
260
50
230
300
65
290 b
340 b
80
310
380
100
350
430
150
480
550
200
600
650
250
730
775
300
850
900
400
1 100
1 150
±2
±3
Source: Table 2 of EN 60534-3-1:2000 with the addition of PN 50 and the replacement of PN 100 by PN 110 (nominal pressure in accordance with the relevant parts of ISO 7005 – some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1).
24
a
In some countries the group PN 10/16/25/40/50 includes also PN 6.
b
Face-to-face dimensions according to Table 2 of IEC 60534-3.
EN 334:2005 (E)
Table 3 — Face-to-face dimensions for flangeless regulators Nominal size
Face-to-face dimensions in mm
Limit deviations for face-to-face dimensions in mm
25
102
±2
40
114
±2
50
124
±2
80
165
±2
100
194
±2
150
229
±2
200
243
±2
250
297
±2
300
338
±3
400
400
±3
DN
NOTE 1
Nominal pressures: PN 10/16/20/25/40/50/110. In some countries this group includes also PN 6.
NOTE 2 Face-to-face dimensions do not include any allowances for gaskets to seal the joints between the regulator ends and the pipeline flanges. Source: EN 60534-3-2 (nominal pressure in accordance with the relevant parts of ISO 7005 – some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1).
Table 4 — Face-to-face dimensions for flangeless regulators Nominal size
Face-to-face dimensions in mm
DN
PN 10/16/20/25/40/50 a
PN 110
Limit deviations for face-to-face dimensions in mm
25
77
86,5
± 1,5
40
77
86,5
± 1,5
50
77
86,5
± 1,5
80
94
104
± 1,5
100
114
133
± 1,5
150
140
175
± 1,5
200
171
205
± 1,5
250
203
240
± 2,5
300
240
280
± 2,5
400
320
350
± 2,5
NOTE 1 Face-to-face dimensions do not include any allowances for gaskets to seal the joints between the regulator ends and the pipeline flanges. NOTE 2 Nominal pressure in accordance with the relevant parts of ISO 7005 (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4 and EN 1759-1). a
In some countries the group PN 10/16/20/25/40/50 includes also PN 6.
25
EN 334:2005 (E)
4.1.6
Sealing of the adjusting device
A means for sealing the adjusting device shall be pr ovided. If requested in the order specification the a djusting device shall be sealed. 4.1.7
Replacement of part affected by erosion or abrasion
The seat ring shall be replaceable where erosion or abrasion occurs.
4.2 Materials 4.2.1
Requirements for metallic materials
4.2.1.1
Pressure containing parts and inner metallic partition walls
The pressure containing parts, including those that become pressure containing parts in the event of diaphragm or differential pressure seal failure, and the inner metallic partition walls can be constructed of:
materials complying with the restrictions given in Table 5 and an established national or an international standard;
or materials given in Annex H.
The internal components of regulators not subjected to differential pressure, may be constructed of either the materials given in Annex H or materials complying with the requirements given in Table 5, without taking into account the restrictions for pressures and nominal sizes, or of different materials provided they comply with the requirements of this document. 4.2.1.2
Material certificates of pressure containing parts and inner metallic partition walls
Pressure containing parts and inner metallic partition walls:
bodies used in the regulators category II, III and IV according to Annex II of PED, shall be accompanied by a material inspection document type 3.2 in accordance with EN 10204. For these bodies when the material manufacturer has an appropriate quality-assurance system, certified by a competent body established within the EC and having undergone a specific assessment for materials, an inspection document type 3.1 in accordance with EN 10204 may be used;
bodies used in the regulators category I according to Annex II of PED, shall be accompanied by an inspection document type 2.2 in accordance with EN 10204.
Pressure containing parts and inner metallic partition walls of other components used for regulators with:
PS ≤ 25 can be accompanied by an inspection document at least type 2.2 in accordance with EN 10204;
PS > 25 shall be accompanied by an inspection document at least type 3.1 in accordance with EN 10204.
4.2.1.3
Fasteners, integral process and sensing lines and connectors
Fasteners, integral process and sensing lines and connectors can be made of:
26
materials complying with the restrictions given in Table 5 and with a national or an international established standard; or materials given in Annex H.
EN 334:2005 (E)
4.2.1.4
Material certificates of fasteners and compression fittings
Bolts, screws, studs, nuts and compression fittings used in the pressure containing parts of the regulators shall bear the marking in accordance with the relevant document and they shall be accompanied by an inspection document type 2.2 in accordance with EN 10204.
27
EN 334:2005 (E)
Table 5 — Materials Restrictions Material Group
Regulator Properties Amin a
PSmax
(PS · DN b)max
DN bmax
%
bar
bar · mm
mm
Pressure containing parts and inner metallic partition walls Rolled and forged steel c
16
100
-
-
Cast steel c
15
100
-
-
Spheroidal graphite cast iron d
7
20
1 500
1 000
15
50
5 000
300
Malleable cast iron
6
20
1 000
100
Copper-zinc wrought alloys
15
100
-
25
Copper-tin and copper-zinc cast alloys
5
20
1 000
100
15
100
-
25
4
20
-
50
7
50
-
50
100
-
25
1,5
10
250
150
4
20
1 600
1 000
Aluminium wrought alloys
Aluminium cast alloys
Integral process and sensing lines Copper
-
25
-
-
Steel
-
100
-
-
-
-
-
9
50
-
-
12
100
-
-
Connectors Steel
8 Fasteners
Steel for bolts, screws, studs
NOTE For castings the specified mechanical characteristics are those measured on machined test piece prepared from separately cast test samples in accordance with the relevant document for the selected materials. a
A = percentage elongation after f racture (according to the applicable document relevant to the chosen material).
b
For the bodies of pilots or fixtures this term shall refer to their inlet connections.
c
Bending rupture energy measured in accordance with EN 10045-1 shall be not less than 27 J at minimum operating temperature (-10 °C or -20 °C). d
Bending rupture energy measured in accordance with EN 10045-1 shall be not less than 12 J as an average of three test pieces and no less than 9 J as a minimum individual value at a temperature of -20 °C for PS > 25 bar when used in regulator class 2.
28
EN 334:2005 (E)
4.2.1.5
Manufacturing
The manufacturer shall state the selected material standards in the relevant documentation (see 8.1.1). Fabrication welds in all pressure containing parts shall be made using qualified welding procedures, by qualified welders or welding operators according to the relevant part of EN 288, EN 287 and EN 1418. In addition, for fabrication welds to make bodies, blind flanges, bonnets and actuator casings:
only full penetration welds shall be used;
weld fabrication and heat-treatment shall comply with EN 13445-4.
These additional requirements are not applicable to seal welding. For all pressure containing parts and inner metallic partition walls, the manufacturer shall identify the material throughout the production from receipt up to the final routine tests by markings or labelling. 4.2.1.6
Non destructive testing (NDT)
Steel bodies shall be non-destructively tested in accordance with Tables 6 and 7.
29
EN 334:2005 (E)
Table 6 — Non destructive testing Type of non destructive testing Volumetric
Steel castings
d b e e n g i a m r a e x v e o c e f b o o t n t e a t s x n e o r i t / o c d e n S a
Surface
Radiographic
Ultrasonic
Visual
ASME B16.34:1996, 8.3.1.1
ASME B16.34:1996, 8.3.1.3
Accessible surfaces
Forgings, bars, plates and tubular products
ASME B16.34:1996, 8.3.2.1
Not applicable
Fabrication welds
According to E and F in Table 7
Accessible surfaces
Magnetic particle
Liquid penetrant
ASME B16.34:1996, 8.3.1.2
ASME B16.34:1996, 8.3.2.2
According to B in Table 7
NDT procedures and acceptance criteria for castings, forgings and their fusion weld repairs b
ASME B16.34:1996, Annex B
ASME B16.34:1996, Annex E
MSS SP 55:1985 c and EN 970 d
ASME B16.34:1996, Annex C
ASME B16.34:1996, Annex D
NDT procedures and acceptance criteria for fabrication welds, including their repairs b
Class B in EN 1435, acceptance level 2 in EN 12517
EN 1713, examination level B in EN 1714, acceptance level 2 in EN 1712
EN 970
EN 1290, acceptance level 2 in EN 1291
EN 571-1, acceptance level 1 in EN 1289
s t n e m e r i u q e r l a r e n e G
•
Examinations shall be performed on the material after any heat treatment required by the material or welding procedure specification, either before or after the finish machining at the option of the manufacturer.
•
Accessible surfaces in case of surface examination include exterior and interior surfaces but no threads, drilled or threaded holes etc.
•
Volumetric examination on castings and full penetration butt welds up to 60 mm thickness should be done radiographically and ultrasonically on forgings and other (full penetration) welds, however one of these techniques may substitute the other provided that the purchaser agrees and it can be demonstrated that interpretable results are produced.
NOTE The concerned parts of ASME B16.34:1996 will be replaced by the equivalent document when it is available. At the time of writing this subject is under study by prEN 12516-1. a
In the case of flanged bodies, the fillets between the line-flanges and the body shall be examined instead of the welding ends to an extent equivalent to that for the bonnet flange in Figures 10 and 11 of ASME B16.34:1996. For bodies of a fundamentally different shape, it may be necessary to define other critical sections, based on experience gained from pilot castings. b
If equivalent national standards exist that cover all relevant aspects they may be used instead. Where equivalent ISO or EN standards are available that cover all relevant aspects they shall be applied. c
This document is applicable only to steel castings.
d
This document is applicable only to fusion weld repairs.
30
EN 334:2005 (E)
Table 7 — Minimum inspection sample pmax
DN < 100
Castings
100
A + B
≥ 100
≥ 150
≥ 200
< 150
< 200
< 250
A+C
A + C
A
< 50
Full penetration fabrication welds Partial penetration fabrication welds
100
A+D
A + B
50 ≤ pmax < 100
Forgings, bars, plates and tubular products
≥ 250
/
50 ≤ pmax < 100
C
C
D
/
> 16
A + F
5 < pmax ≤ 16
A + E
> 16
A + B
A
is the visual examination of 100 % of the production batch.
B
is the magnetic particle or liquid penetrant examination of 100 % of the production batch.
C
is the volumetric examination of 10 % of the production batch, selected on random basis.
D
is the volumetric examination of 20 % of the production batch, selected on random basis.
E is the volumetric examination of 10 % of the circumferential, corner and nozzle seams of the production batch, selected on random basis, and 100 % of the longitudinal seams of the production batch. F is the volumetric examination of 20 % of the circumferential, corner and nozzle seams of the production batch, selected on random basis, and 100 % of the longitudinal seams of the production batch.
NOTE A production batch consists of castings or forgings from the same melt and the same heat treatment or welds made by the same process and/or welder or welding operator. An inspection sample is a percentage of the production batch.
In the case of random inspection, if a casting, forging or weld does not conform to the acceptance criteria, a further inspection sample of twice the original sample size from the production batch shall be examined. If one of these castings, forgings or welds fails, the examination shall be extended to all castings, forgings or welds in the production batch. Any casting, forging or weld that does not conform to the acceptance criteria shall be repaired according to an applicable procedure and then re-examined. The NDTs shall be carried out by qualified personnel in accordance with EN 473 or other equivalent documents. 4.2.2
Requirements for elastomers (including vulcanized rubbers)
Elastomers shall comply with suitable requirements (at the time of the writing this subject is under study in WI 00235009 - prEN 13787 rev.). 4.2.3
Requirements for non metallic materials different from those in 4.2.2
Functional non metallic parts in contact with the gas shall be chemically resistant to the fuel gases listed in Clause 1 and to the additive substances normally used for odorization and conditioning of gases. Furthermore, these materials shall be resistant to the permissible impurities in the gas.
31
EN 334:2005 (E)
The effect of liquids on functional non metallic parts shall comply with the requirements in Table 8. After immersion for one week at 23 °C ± 2 °C in test liquid A (100 % n-pentane) as specified in ISO 1817, followed by drying in an oven at 70 °C ± 2 °C, the change in mass when determined by the method specified in 5.4 of EN ISO 175:2000 shall comply the requirements in Table 8. Table 8 – Requirements for non metallic materials different than those in 4.2.2 Property
Determination of changes in mass
Requirements
Maximum change in mass after one week at 23 °C ± 2 °C
EN ISO 175
±5%
Maximum change in mass after drying in an oven at 70 °C ± 2 °C
EN ISO 175
+5 % /-2 %
4.3 Strength of housings 4.3.1 4.3.1.1
Body and its inner metallic partition walls General
The limit pressure pl (determined or calculated in accordance with 7.7.3), maximum allowable pressure PS and maximum inlet pressure pumax shall be as follows: pl ≥ Sb 4.3.1.2
× PS ≥
Sb × pumax
Flanges
The maximum allowable operating pressure for flanges in accordance with the relevant parts of ISO 7005 shall not be less than maximum allowable pressure PS (some parts of these documents can be replaced by the equivalent documents when they are available. At the time of writing, this subject is dealt with in EN 10921, EN 1092-2, EN 1092-3, EN 1092-4, EN 1759-3, EN 1759-4 and EN 1759-1). 4.3.2
Other pressure containing parts for integral strength pressure regulators
Those parts subjected to pressure under normal operating conditions, or those that become pressure containing parts in the event of a failure (casing of actuator, pilot, fixtures, etc.), shall have a limit pressure pl and a maximum allowable pressure PS, complying with the following requirements: pI ≥ S × PS 4.3.3
≥
S × pumax
Other pressure containing parts for differential strength pressure regulators
Such regulators have pressure containing parts which in the event of a failure are protected from pressures reaching pumax by specific safety devices e.g., relief valves, a vent tapping or a bleed via the sensing or process lines. These pressure containing parts shall have the maximum pressure pmax reached in the event of a failure and the limit pressure pl complying with the following requirement: pl ≥ S × pmax For markings see Clause 9.
32
EN 334:2005 (E)
4.3.4
Inner metallic partition walls
Where a chamber in the regulator is separated into individual pressure containing chambers by a metallic partition wall, it shall be designed taking into account the highest possible pressure relative to the lowest pressure possible in the adjoining chamber. The following requirement shall be complied with: pl ≥ S × ∆ pmax 4.3.5
Minimum values of safety factor
The values listed in Table 9 shall be used to limit the stresses in the walls of pressure containing parts and inner metallic partition walls at the maximum allowable pressure. The values of the safety factors applicable to diaphragms when they have both the function of pressure containing parts and inner metallic partition wall are those detailed in 7.7.3.2. Table 9 — Minimum values of safety factor Group of materials
Minimum value of safety fa ctor
S
For parts of the body stressed by forces from pipelines only Sb
Rolled and forged steel
1,7
2,13
Cast steel
2,0
2,5
Spheroidal graphite cast iron and malleable cast iron
2,5
3,13
Copper-zinc wrought alloys aluminium wrought alloys
and
2,0
2,5
Copper-tin cast alloys and copperzinc cast alloys
2,5
3,13
Aluminium cast alloys Amin 4 %
2,5
3,13
Aluminium cast alloys Amin 1,5 %
3,2
4,0
4.3.6
Welded joint coefficient
For welded joints both in pressure containing parts and into inner metallic partition walls, the welded joint coefficient shall not exceed the following values:
for regulators subject to NDTs which confirm that the whole series of joints show no significant defects: 1;
for regulators subject to random NDTs: 0,85;
for regulators not subjected to NDTs other than visual inspection: 0,7.
33
EN 334:2005 (E)
5
Functional requirements
5.1 General 5.1.1
Mounting position
Regulators within the scope of this document shall function in any mounting position specified by the manufacturer, ± 5°. 5.1.2
Sound emission
On request in the order specification, the sound pressure level LpA of the regulator shall be given for the operating conditions for which it has been ordered if the expected LpA of the regulator exceeds 70 dB. The operating conditions are directly related to:
the inlet pressure;
the outlet pressure;
the volumetric flow rate;
the type of gas.
On request in the order specification, the manufacturer shall also supply the following information for specified operating conditions:
the likely spectral octave band of the noise level with centre frequencies of 500 Hz through to 8 000 Hz;
sound pressure level below 70 dB.
On request in the order specification the manufacturer shall supply the calculation method for sound emission and likely spectral octave band of the noise level with centre frequencies of 500 Hz through to 8 000 Hz. With reference to the wide variety of different operating conditions and data, it may be appropriate to determine the noise level by calculation.
Measured sound pressure level: the declared LpA shall be measured in accordance with 7.7.7.4.6 and shall be related to the points of measurement indicated in Figure 7 at the same height as the regulator.
Calculated sound pressure level: the declared LpA shall be calculated using a method established by the manufacturer.
The accuracy of the sound pressure measurement or the calculated sound pressure level shall be given and shall not exceed 5 dB.
34
EN 334:2005 (E)
Key 1
Standard measurement points
Figure 7 — Points of measurement for sound pressure level
5.2 Shell strength, external tightness and internal sealing 5.2.1
Shell strength
Pressure containing parts subjected to the test in 7.7.4 shall show no visible leakage and no permanent deformations exceeding 0,2 % or 0,1 mm, whichever is greater. The percentage of the permanent deformation is calculated as:
100 ×
l − l 0 l
where l 0 is the distance between any two points on a pressure containing part before applying the test pressure; l 5.2.2
is the distance between the same points after releasing the test pressure. External tightness
The pressure containing parts and all connecting joints shall be leak-proof when tested in accordance with 7.7.6. 5.2.3
Internal sealing
The control member in its closed position and inner metallic partition walls which are subjected to inlet pressure shall seal in accordance with the requirements of 7.7.7.3 or 7.7.7.4.3.
35
EN 334:2005 (E)
5.3 Control classifications 5.3.1 5.3.1.1
Accuracy under stable conditions Accuracy classes
Regulators shall conform to accuracy requirements relevant to the declared accuracy class(es) chosen from Table 10. Table 10 — Accuracy classes Accuracy class
a
Permissible positive and negative regulation change
AC 1
± 1%a
AC 2,5
± 2,5 % a
AC 5
± 5%a
AC 10
± 10 %
AC 20
± 20 %
AC 30
± 30 %
But not lower than ± 1 mbar.
The same type of regulator may have different accuracy classes depending on the set range W d and/or the inlet pressure range bpu. 5.3.1.2
Hysteresis
The hysteresis is included in the accuracy class and shall be declared by the manufacturer if requested in the order specification. 5.3.2 5.3.2.1
Lock-up behaviour Lock-up pressure classes
Regulators shall conform to lock-up pressure requirements relevant to the declared class(es) chosen from Table 11. Table 11 — Lock-up pressure classes Lock-up pressure class
a
36
Permissible positive regulation change within the lock-up pressure zone
SG 2,5
2,5 % a
SG 5
5%a
SG 10
10 %
SG 20
20 %
SG 30
30 %
SG 50
50 %
But not lower than 1 mbar.
EN 334:2005 (E)
The same type of regulator may have different lock-up pressure classes depending on the specified set range W d and/or the inlet pressure range bpu. At the lowest limit temperature the permissible deviation for the declared lock-up pressure classes may move to a less stringent class as detailed in 7.7.7.4.5. 5.3.2.2
Classes of lock-up pressure zone
Regulators shall conform to lock-up pressure zone requirements relevant to the declared class(es) chosen from Table 12. Table 12 — Lock-up pressure zone classes Class of lock-up pressure zone
Limit value of the l ock-up pressure zone as a percentage of Qmin,pu to Qmax,pu
SZ 2,5
2,5 %
SZ 5
5%
SZ 10
10 %
SZ 20
20 %
Within the lock-up pressure zone the regulator need not comply with 5.3.3. The same type of regulator may have different classes of lock-up pressure zone depending on the set range W d and/or the inlet range bpu. 5.3.3
Stable conditions
For the permissible positive and negative regulator change specified in 5.3.1.1 the amplitude of any oscillations occurring in steady state shall not exceed 20 % of the accuracy class but with a lower limit of 1 mbar.
5.4 Final visual inspection In the type test specifically after the tests 7.7.4 up to and including 7.7.7.4.5 and test 7.7.7.4.6 when applicable, excluding the test in 7.7.7.3, the regulator shall show no undue wear, binding, corrosion, damage or other defects which may affect its long term performance.
5.5 Fail-close conditions In the regulator fail-close type the control member shall tends to close or close in the following cases:
damage of main diaphragm;
failure of energy to move the control member.
6
Gas pressure regulator sizing
6.1 Flow behaviour The flow behaviour of a regulator is said to be critical if at constant inlet temperature the volumetric flow rate varies proportionally only with the absolute inlet pressure.
37
EN 334:2005 (E)
The flow behaviour of a regulator is said to be sub-critical if at constant inlet temperature the volumetric flow rate varies with both the absolute inlet and outlet pressures. The boundaries of the critical and sub-critical flow behaviour (see Equation (9) in 7.7.7.2.2) are shown in the system of Cartesian coordinates shown in Figure 8 and coincide with the two different sections of the plotted curve. For the definition of the symbols see 6.2.
pe + pb p + p critical b a Key 1
Linear section
2
Non linear section
3
Sub-critical behaviour
4
Critical behaviour
Figure 8 — Flow behaviour of a regulator with the control member in a fixed position
6.2 Sizing equations for the calculation of volumetric flow rates of a gas pressure regulator with its control member in its mechanically fully open position 6.2.1
Normal calculations
Volumetric flow rates should be calculated using the sizing equations of EN 60534-2-1. 6.2.2
Practical calculations
Normally, in the regulators field it is common to use the following equations: a) sub-critical flow behaviour
Q=
13,57 d (t u + 273)
C g
p u
+ p b
2
p u - p d
p u + p b
sin K 1
deg
b) critical flow behaviour (see Equation (9) in 7.7.7.2.2)
38
(3)
EN 334:2005 (E)
Q=
13,57 d (t u + 273)
C g
p u
+ p b
2
(4)
where C g is the flow coefficient; d
is the relative density (air = 1, non dimensional value);
K 1 is the body shape factor; pb is the ambient atmospheric pressure in bar (absolute value); t u 6.2.3
is the gas temperature at the inlet of the regulator under test in °C. Simplified calculations
If K 1 ≤ 130 and ( pu - pd) > 0,1 ( pu + pb) the following simplified equations may be used with an error less than 10 %: a) sub-critical flow behaviour, where ( pu - pd) ≤ 0,5 ( pu + pb): Q=
13,57 d (t u + 273)
( p d + p b ) ( p u - p d )
C g
(5)
b) critical flow behaviour, where ( pu - pd) > 0,5 ( pu + pb): Q=
13,57 d (t u + 273)
C g
p u
+ p b
2
(6)
Conversion of the flow coefficients may be carried out by making reference to EN 60534-2-1.
NOTE
The expression
13,57 d (t u + 273)
C g is also known as K G.
6.3 Calculation of the maximum accuracy flow rate The maximum accuracy flow rate should be calculated from the equations given in 6.2 by using the applicable percentage of the flow coefficient at fully open position. This percentage which is equal to or less than 100, depends on the accuracy class AC and shall always be specified by the manufacturer (see Figures 5 and 9).
6.4 Inherent flow characteristics The relationship between flow coefficient and the position of the control member is usually represented diagrammatically (see Figure 9). Flow coefficients are usually expressed as a percentage of the flow coefficient at fully open position and the position of the control member as a percentage of the maximum travel (limit imposed by a mechanical stop). Figure 9 gives examples of the inherent flow characteristics of three different types of regulator.
39
EN 334:2005 (E)
6.5 Calculation of volumetric flow rates for partially open gas pressure regulators Volumetric flow rates for regulator positions between closed and fully open shall be calculated using the equations given in 6.2, but by using the percentage of the flow coefficient at fully open position associated with a given percentage of the valve travel as detailed in 6.4.
Key X
Travel in %
Y
C g in %
Figure 9 — Three examples of inherent flow characteristics
6.6 Flow coefficient For all flow coefficients the tolerance between the value declared by the manufacturer and the actual value verified during the type test shall be ± 10 %.
7
Testing
7.1 General Clause 7 provides guidance on the procedure that may be used when a certification of compliance with the requirements of this document is required. The sub-clauses in Clause 7 may be applied also to the conformity assessment to the PED.
7.2 Tests Table 13 gives an overview of the different types of tests and correlates them to the requirements and test methods detailed in Clauses 4, 5 and 7. The requirements in this chapter shall be followed when compliance evaluation with this document is requested. Where compliance evaluation to this document is finalized with positive result, the regulator can bear as marking the number of this document.
40
EN 334:2005 (E)
Table 13 — Summary of tests and requirements Test schedule T
M
Requirement S
Clause
Test method Title
Clause
Constructional tests A
A
A
4.1
Dimensional check and visual inspection
7.7.1
A
A
A
4.2
Materials check
7.7.2
4.3
Verification of the strength of pressure containing parts and inner metallic partition walls
7.7.3
A A
A
A
5.2.1
Shell and inner metallic partition walls strength test
7.7.4
A
A
A
5.2.2
External tightness test
7.7.6
Functional tests A
6.6
Determination of the flow coefficients
7.7.7.2
5.2.3
Check of internal sealing, setting, lock-up pressure and simplified test method for accuracy class
7.7.7.3
A
5.3.1.1 and 5.3.3
Determination of a performance curve and verification of the hysteresis band
7.7.7.4.2
A
5.2.3
Determination of the lock-up pressure and verification of the internal sealing
7.7.7.4.3
A
5.3
Determination of the accuracy class, the lock-up pressure class, the class of lock-up pressure zone, the maximum accuracy flow rate and the minimum flow rate related to a given range of inlet pressures
7.7.7.4.4
A
5.3.2.1
Operational check at the -10 °C or -20 °C and 60 °C
7.7.7.4.5
optional
-
A
5.4
A a
A
A
A
7.7.8.2
limit
temperatures
of
Methods for measuring the sound pressure level
7.7.7.4.6
Final visual inspection after type test
7.7.8.1
Final visual inspection a fter routine tests and production surveillance
7.7.8.2
A = Applicable S = Production surveillance M = Routine tests T = Type test a
Simplified test method for accuracy class is not required in the routine tests.
7.3 Type test Those tests (see Table 13) carried out to establish the performance classification of the regulator or the series of regulators. These tests include verification of the documentation listed in 8.1.1. When changes are made to the design of a regulator or a series of regulators in such a manner as to affect the above tests, the manufacturer shall inform the parties involved, if any, in the compliance evaluation to this document.
41
EN 334:2005 (E)
7.4 Selection of test samples The number and types of a series of regulators to be subjected to a type test shall be selected according to the following requirements:
one regulator for each type of fixture and/or pilot;
two sizes from a series of up to six sizes and three sizes from series greater than six in number;
one regulator for each accuracy class AC, if applicable;
if the series of regulators includes sizes of regulators with more than one valve seat diameter, the test sample shall have the largest valve seat installed.
The check in accordance with 7.7.7.4.5 shall only be carried out on one test sample.
7.5 Routine tests Those tests (see Table 13) carried out on each regulator by the manufacturer during the production process. The tests verify that materials, dimensions, external conditions and performance remain in compliance with the results of the type test. Routine tests for integrated safety devices, if any, shall be those detailed in EN 14382.
7.6 Production surveillance Those tests and verifications (see Table 13) carried out in order to confirm continuing compliance with this document. The tests and verifications include additionally:
verification of the routine tests records;
verification of drawings and material certificates.
7.7 Test and verification methods 7.7.1
Dimensional check and visual inspection
The actions to assess:
the dimensional compliance of pressure containing parts with the applicable drawings;
the compliance of the regulator construction with the pertinent assembly drawing and the construction requirements of this document.
7.7.2
Materials check
The actions to assess the compliance of the materials used or prescribed with the requirements in 4.2. The verification of the materials used shall be carried out by the review of the material certificates. The verification of the materials prescribed shall be carried out by the review of the materials bill.
42
EN 334:2005 (E)
7.7.3
Verification of the strength of pressure containing parts and inner metallic partition walls
7.7.3.1
Strength calculation method
Verification is made by proving the compliance of the actual safety factors with those specified in 4.3.5 and the compliance of minimum allowable thicknesses shown in drawings with values specified in the strength calculations. Strength calculation can be carried out according to EN 12516-2 and prEN 12516-4. 7.7.3.2
Experimental design method
Verification is made by proving the compliance of the actual safety factors with those specified in 4.3.5 taking into account the minimum allowable thicknesses shown in drawings and the minimum proof stress (yielding) for selected material. Actual safety factors are obtained through one of the following two ways:
hydrostatic pressure test applied until the first sign of yielding or failure becomes apparent in any component and verification that the limit pressure pl at which the first sign of yielding or failure becomes apparent is:
pl
pl
≥
≥
PS ÷ S b ×
PS × S ×
sry
×
smin
sry
×
smin
R p 0, 2
r
R p 0, 2
min
R p 0, 2
r
R p 0, 2
for the body only;
for other components;
min
hydrostatic pressure test and verification that permanent deformations do not exceed the values stated in 5.2.1 up to the following test pressures:
0,9 × PS × S b ×
0,9 × PS × S ×
srw sw
srw sw
×
×
R p 0, 2
r
R p 0, 2
min
R p 0, 2
r
R p 0, 2
for the body only;
for other components;
min
where smin
is the minimum design wall thickness at the point where the first sign of yielding occurs in mm;
sry
is the measured wall thickness of test sample at the point where the first sign of yielding occurs in mm;
|R p0,2 |min
is the minimum proof stress (yielding) for selected material according to relevant document in N/mm2;
43
EN 334:2005 (E)
|R p0,2 |r
is the measured proof stress (yielding) for the material of the test sample according to relevant document in N/mm 2;
sw
is the minimum design wall thickness for the weakest point in mm;
srw
is the measured wall thickness of test sample at the weakest point in mm.
The weakest point can be located by technical evaluation or via measurements (strain gauge etc.). The test is carried out in such a manner that deformations of the test sample in all directions are possible. There shall be no additional stresses due to bending, torque or tension. Forces from fastening systems shall be similar to those experienced under normal installation conditions. Regulator bodies and pressure containing parts manufactured from different materials may be pressure tested separately. Special high strength clamping bolts and nuts may be used for hydrostatic testing. Diaphragms used as pressure containing parts in chambers subjected, or that can be subjected to a maximum differential pressure ∆ pmax shall withstand a test pressure (in bar) of at least:
0,3 bar
if ∆ pmax < 0,15 bar;
2 ∆ pmax
if 0,15 bar
1,5 ∆ pmax but at least 10 bar
if ∆ pmax ≥ 5 bar.
7.7.4
≤ ∆ pmax < 5
bar;
Shell and inner metallic partition walls strength test
Pressure containing parts, those that become pressure containing parts in case of a diaphragm or differential pressure seal failure and inner metallic partition walls shall be pressure tested. The test is carried out with water at ambient temperature at a pressure according to the values in Table 14 for 3 min. The criteria of 5.2.1 shall be met. The test is carried out in such a manner that deformations of the test sample in all directions are possible. There shall be no additional stresses due to bending, torque or tension. Forces from fastening systems shall be similar to those experienced under normal installation conditions at least during the type test. The test may be carried out without trim (i.e. the internal parts that are in flowing contact with gas). The test may also be carried out with air or nitrogen, if the necessary safety measures are taken. Chambers separated by diaphragms are pressurized on both sides of the diaphragm at equal pressure.
44
EN 334:2005 (E)
Table 14 — Pressure values for the shell strength test Chambers subjected or that can be subjected to gas pressure
Individual pressure containing chamber at highest pressure limited, at least at one side, by an inner metallic partition wall
Chambers safeguarded in accordance with 4.3.3 subjected, or that can be subjected to a gas pressure
Test pressures 1,5 PS but at least PS + 2 bar whichever is the greater
7.7.5
but at least ∆ pmax + 2 bar
1,5 pmax but at least pmax + 2 bar
whichever is the greater
whichever is the greater
1,5 ∆ pmax
Alternative shell and inner metallic partition walls strength test
Hydrostatic pressure tests as detailed in 7.7.4 may be replaced by other tests (e.g. pneumatic test) whose reliability shall be demonstrated. For tests other than the hydrostatic pressure test, additional safety measures, when appropriate, such as non-destructive tests or other methods of equivalent validity, shall be applied before those tests are carried out. 7.7.6 7.7.6.1
External tightness test External tightness test of metallic housing
The assembled regulator and its fixtures are pneumatically tested to assess compliance with the requirements of 5.2.2. The test is carried out at ambient temperature with air or gas at the test pressure specified in Table 15. This test shall be carried out on a strength-tested regulator for at least:
15 min in the type test;
1 min in the routine tests and in the production surveillance.
The result of the test is satisfactory if one of the following conditions is met:
bubble tight for a time of 5 s. This test may be carried out by covering the regulator with a foaming liquid, by immersing the regulator in a tank of water or by other equivalent methods;
external leakage not higher than the values listed in Table 16.
The test pressures in Table 15 do not apply to any chambers bounded on at least one side by a diaphragm even if they are subjected to gas pressure under normal operating conditions. The test is carried out in such a manner that deformations of the test sample in all directions are possible. There shall be no additional stresses due to bending, torque or tension. Forces from fastening systems shall be similar to those experienced under normal installation conditions at least during the type test. Recognized alternative detection methods may be used for checking leakage (e.g. electronic device). For such methods the equivalence to the above requirements shall be demonstrated.
45
EN 334:2005 (E)
Table 15 — Pressure values in the external tightness test Chambers subjected, or that can be subjected to gas pressures
Chambers safeguarded in accordance with 4.3.3, subjected, or that can be subjected to gas pressure
≤ pd a
> pd
Test pressures 1,1 PS
a
1,2 p 1,2 pds max but at least 0,5 PS whichever is the greater
1,1 p 1,1 pmax
Only if PS ≤ 20 bar. For PS > 20 bar the test pressure shall be 1,1 PS.
Table 16 — Maximum external and internal leakage rates Air leakage rate in cm3/h a
Nominal size DN external
internal b
25
40
15
40 to 80
60
25
100 to 150
100
40
200 to 250
150
60
300 to 350
200
100
400
400
300
a
At normal conditions.
b
In case of specific specific requirement in the the order order specification, specification, see Annex Annex E.
7.7.6.2
External tightness test of chambers bounded on at least one side by a diaphragm
Such chambers shall be pneumatically tested at a test pressure (in bar) equal to at least:
0,2 bar
1,33 ∆ pmax
1,1 ∆ pmax but at least 6,65 bar
if ∆ pmax < 0,15 bar; if 0,15 bar
≤ ∆ pmax < 5
bar;
if ∆ pmax ≥ 5 bar.
Test method and acceptance criteria in accordance with 7.7.6.1. 7.7.7 7.7.7.1
Functional tests General conditions
If the regulator has built-in safety device(s) it shall be tested with the safety device(s) in its (their) normal operating position. The tests may be carried out either with air or with gas. Where necessary, measured volumetric flow rates shall be converted into values that are related to air at normal conditions. Due to the need to obtain a homogeneous set of test results that will permit different types of regulators to be compared with each other, or to assess in the laboratory the requested performance of a regulator in the field, or make the assessments
46
EN 334:2005 (E)
specified in 7.7.7.4, the measured values shall be converted into volumetric flow rates related to an inlet reference temperature of 15 °C. Pressure gauges shall have an accuracy of at least AC/4 across the scale range according to the applicable document and a full scale not greater than twice the value of the variable to be measured. Tests shall be carried out at ambient temperature. Regulators shall be tested in the mounting position specified by the manufacturer. The external sensing/process lines shall be located on the downstream pipework according to the recommendations of the manufacturer. 7.7.7.2
Determination of the flow coefficients
7.7.7.2.1
Normal method
If the volumetric flow rates are calculated using the sizing equations of EN 60534-2-1, the tests shall be carried out in accordance with EN 60534-2-3. 7.7.7.2.2
Practical method
If in the flow calculation the equations given in 6.2 are being used then the following equations shall be used to calculate flow coefficient C g and the body shape factor K 1. To determine C g of a regulator with the control member in the mechanically fully open position it is necessary to plot a diagram as shown in Figure 8 of 6.1. The C g shall be determined for at least three different operating conditions in the critical flow behaviour with:
C g =
2Q
d (t u + 273)
13,57 ( p u + p b )
(7)
The C g flow coefficient shall be assumed to be equal to the arithmetic mean of the three values. The shape factor K 1 (see 6.2.2) shall be determined for at least three different operating conditions in the sub-critical flow behaviour with:
Q
arcsin
K 1 =
d (t u + 273) 13,57 C g
p u + p b deg 2
p u - p d
(8)
p u + p b
The shape factor K 1 shall be assumed to be equal to the arithmetic mean of the three values. For C g and K 1 shape values a tolerance of ± 10 % is permitted. The behaviour shall be assumed to be critical when: pu + p b pd + p b
≥
1
90 1 − K 1
2
=
K 1 2
2
K 1 - 8100
(9)
In the equations (7) and (8) Q is the volumetric flow rate at normal conditions of the test fluid as measured by the flow meter 9 in Figure 14. The measured values shall be converted into values related to the normal conditions specified in 3.2.1.2.1. The calculation of Q shall be carried out using the following equation:
47
EN 334:2005 (E)
p + pb T n Q= M QM pn t M + T n
=
p + pb 269,64 M QM t M + 273
(10)
where for p for pn and T and T n see 3.2.1.2.1; pM is the gas gas pressure at the flow meter; QM is the volumetric flow rate measured at the flow meter; t M is the gas temperature at the flow meter in °C. The tests shall be carried out where technical possible and economically justified on a test rig in accordance with 7.7.7.4.7. Where this is not the case, alternative test and calculation methods e.g. that detailed in A.3 may be used for the determination of flow coefficient C g. 7.7.7.3 Check of internal sealing, set point, lock-up pressure class and simplified test method for accuracy class
These tests shall be carried out with volumetric flow rates greater than Qmin,pu at the extreme values of the inlet pressure range bpu for the setting of the controlled pressure or for the extreme values of specific set range W ds or for the extreme values of set range W d according to the order specification. Initial conditions to be set as follows:
inlet pressure to be equal to to p pumin and the volumetric flow rate to be zero;
increase the volumetric flow rate to the level specified above;
adjust the controlled pressure to the required set point.
The test for each setting shall comprise the following steps (see Figure 10): a) reduce the volumetric volumetric flow rate until complete lock-up lock-up takes place within a period not less than the response time of the regulator; b) record the lock-up pressure:
after 5 s;
after 30 s
from the closure of the regulator; NOTE 1
c)
These values are not appropriate for pilot controlled regulators.
increase the volumetric flow rate close to the above value and determine the corresponding outlet pressure p pressure pd;
d) increase the inlet pressure until p until pumax is reached; e) measure the value of outlet pressure pd; f)
48
repeat the above above steps from a) to c) without without any any further adjustment of the setting;
EN 334:2005 (E)
g) reduce the volumetric flow rate until complete lock-up takes place within a period not less than the response time of the regulator; h) increase the inlet pressure up to 1,1 PS; i)
record the lock-up pressure:
after 5 s;
after 30 s
from the closure of the regulator; NOTE 2
These values are not appropriate for pilot controlled regulators.
Provided the values of lock-up pressure at 5 s and 30 s are comparable, taking account of the accuracy of the measuring system, it shall be assumed that the regulator has passed the internal leakage test. The values of lock-up pressure, the outlet pressures resulting from the two increases in the volumetric flow rate and the setting shall be within the applicable range. If the manufacturer is unable to provide the required test volumetric flow rate, an alternative test procedure may be used to cover these checks. In these verifications a test rig in accordance with 7.7.7.4.7 is not mandatory. If a detection method is available to verify compliance with the required internal leakage rates given in Table 16, an alternative procedure may be followed to check the internal sealing and to measure the lock-up pressure at pumin and pumax. In this case the determined leakage rates shall comply with:
the requirements of Table 16 or
the requirements of EN 1349 if specified in the order specification (see Annexes E and G).
49
EN 334:2005 (E)
Key 1
pumin
2
pumax Setting Measured value
Figure 10 — Graphical representation of the tests detailed in 7.7.7.3 7.7.7.4 7.7.7.4.1
Functional tests under stable conditions General conditions
These tests shall be carried out at ambient temperature. The purpose is to verify the values stated by the manufacturer for the:
accuracy class;
maximum hysteresis band, if specified in the order specification;
lock-up pressure class;
class of lock-up pressure zone;
maximum accuracy flow rate and minimum flow rate.
The tests shall be carried out where technically possible and economically justified on a test rig in accordance with 7.7.7.4.7. Where this is not the case, alternative test and calculation methods e.g. those explained in Annex A or the modelling tests on test specimens to a smaller scale as described in EN 60534-2-3, may be used for the determination of Qmax,pumin, Qmax,pumax, AC, SG and hysteresis band if specified in the order specification under the following pre-conditions: a) the maximum possible size and at least the minimum size of a series of regulators shall be tested using a test rig in accordance with 7.7.7.4.7; b) to prove that the alternative method chosen is reliable by comparing the results with those from a test at full operating conditions in a particular regulator size; c)
50
to use the alternative method for larger sizes of regulators of the same series.
EN 334:2005 (E)
However, if the regulator or even the smallest regulator of a series can not be tested using a test rig in accordance with 7.7.7.4.7, the test method as detailed in Annex A may be used without other pre-conditions. The compliance with performance requirements shall be checked against only three families of performance curves for three different values of outlet pressure chosen within the set range W d in accordance with the following criteria: pdmin pdmax pdint = pdmin +
pdmax - pdmin
3
For each family of performance curves three values of inlet pressure shall be chosen within the inlet pressure range bpu in accordance with the following criteria: pumin pumax puav =
pumin + pumax
2
(rounded to the nearest whole number)
The regulator shall be kept pressurized throughout the whole process with no interruption of this condition until the determination of the families of performance curves is completed. 7.7.7.4.2
Determination of a performance curve and verification of the hysteresis band
With the understanding that the "actual set point" cannot be determined at the outset of this process, the setting of the regulator shall be adjusted at:
an inlet pressure equal to puav;
the volumetric flow rate recommended by the manufacturer.
Changes to the setting prior to the completion of the whole process for the determination of a single performance curve, or families of performance curves, are not permitted. The flow rate regulating valve 8 (Figure 14) shall be used to vary the volumetric flow rates. The operating time of the valve shall not be less than the response time of the regulator as specified by the manufacturer. Volumetric flow rates measured by the flow meter 9 (Figure 14) shall be recalculated to refer to:
normal conditions (see 3.2.1.2.1);
air at the reference temperature of 15 °C at the inlet of the regulator under test.
To this end the following equation shall be used:
Q = QM
p M
+ p b
p n
T n t M
d (t u
+ T n
+
273)
1(15 + T n )
= 15,88
p M + p b t M + 273
QM
d (t u + 273)
(11)
where for pn and T n see 3.2.1.2.1;
51
EN 334:2005 (E)
d
is the relative density of the test fluid (air = 1 non dimensional value);
pM is the gas pressure at the flow meter; QM is the volumetric flow rate measured at the flow meter; t M is the gas temperature at the flow meter in °C; t u
is the gas temperature in °C at the inlet of regulator under test.
At least 11 different measurements conveniently distributed over the full range of values between Qmin and Qmax (5 with volumetric flow rates increasing, 4 with volumetric flow rates decreasing, an additional measurement at zero volumetric flow rate and one at the start setting) shall be taken for each pair of pu and pds values. Figure 3 is an example of a chart showing the relevant details such as the start setting, the measured results and the performance curve for the controlled variable related to a single pair of pu and pds values. 7.7.7.4.3
Determination of the lock-up pressure and verification of the internal sealing
The lock-up pressure shall be determined in connection with tests carried out to determine the performance curve of the controlled variable. The time required to reduce the volumetric flow rate to zero shall not be less than the lock-up time of the regulator. This condition is deemed to be satisfied when the lock-up pressure is found to be independent of the time needed to reduce the volumetric flow rate to zero (see Figure 11).
X
Time to reduce the volumetric flow rate to zero
Y
Pressure with control member at closing position
Figure 11 — Graphical representation of 7.7.7.4.3
The lock-up pressure pf shall be measured twice, after 1 min and after 2 min from the regulator closure. When the inlet pressure is greater than 16 bar the second measurement shall be taken after 5 min. Any lock-up pressure value that can be affected by temperature variation in the fluid contained in the volume between the regulator under test and the flow rate regulating valve, shall be recalculated and related to the initial temperature by using the following equation: pf =
52
t + 273 t i + 273
( pfi + pb ) - pb
(12)
EN 334:2005 (E)
where pb is the absolute ambient pressure; pfi is the lock-up pressure related to the second measurement; t
is the gas temperature in °C related to the first measurement;
t i
is the gas temperature in °C related to the second measurement.
The regulator shall be deemed leak-tight if the last two lock-up pressures, corrected for the initial temperature, are comparable (taking account of the accuracy of the measuring system) or comply with the internal leakage rate requirements given in:
Table 16 or
EN 1349 if specified in the order specification (see Annexes E and G).
The lock-up pressures of the regulator shall be within the applicable range. For lock-up pressure measurements the outlet pipework of the test rig shall have a minimum length as specified in Figure 14. The internal sealing of regulator shall also be verified at:
inlet pressure of 1,1 PS;
outlet pressure of zero.
7.7.7.4.4 Determination of the accuracy class, the lock-up pressure class, the class of lock-up pressure zone, the maximum accuracy flow rate and the minimum flow rate related to a given range of inlet pressures
The determination is based on optimal enveloping of each family of performance curves with the vertical and horizontal limit lines as shown in Figure 5. An example of an optimal enveloping procedure is shown in Figure 12 and is described as follows:
plot the performance curves of a family in a semilog diagram with volumetric flow rates on the decimal scale of the abscissa and outlet pressure on the logarithmic scale of the ordinate;
locate on this diagram, in an optimized manner, three horizontal lines spaced as shown in Figure 12; the optimization of the location of these lines is reached when the greatest possible number of performance requirements are met;
identify the actual set point where the dashed horizontal line intersects the ordinate;
ensure that Qmax,puav , Qmax,pumin, Qmax,pumax , Qmin,pumax , Qmin,puav , Qmin,pumin, AC and pf are within the established limits.
Other equivalent optimal enveloping methods may be used. If the performance data listed by the manufacturer are not met, the test report shall detail the actual performance data taken from the type tests.
53
EN 334:2005 (E)
Key 1
Max limit for pf
2
Max limit for pd with Q outside the lock-up zone
3
Min limit for pd
Figure 12 — Graphical example of 7.7.7.4.4 7.7.7.4.5
Operational check at the limit temperatures of –20 °C or –10 °C and 60 °C
The regulator shall be installed in a suitable thermostatically controlled enclosure. To start the check the test medium shall be brought to the relevant temperature. The check shall verify the internal sealing and determine the lock-up pressure in accordance with 7.7.7.4.3 under the following conditions:
max inlet pressure/min outlet pressure;
min inlet pressure/min outlet pressure; at the relevant temperatures.
The lock-up pressure at the -20 °C limit temperature shall be: ≤ pds
2 SG 1 + 100
The lock-up pressure at other limit temperatures shall be: ≤ pds
SG 1 + 100
where pds and SG are those determined at ambient temperature.
54
EN 334:2005 (E)
A check to determine the control member travel of the regulator shall also be carried out at no flow condition in order to demonstrate that the regulator can fully open. If specified in the order specification, alternative methods in accordance with Annex A may be used. After this check, the test in accordance with 7.7.6 is repeated at the lower limit temperatures. 7.7.7.4.6
Methods for measuring the sound pressure level
The fully assembled regulator with all its fixtures shall be installed:
at between 0,8 m and 1,2 m above floor level;
in accordance with the requirements specified in 7.7.7.4.7 with regard to the velocities of the gas in the test rig.
The floor shall be one of normal concrete or similar construction. Care shall be taken to ensure that any possible effects of sound emissions other than the noise generated by the regulator are excluded (for example noise generated by the flow rate regulating valve or the external environment). The points of measurement of sound emission shall be in accordance with Figure 7. The sound pressure level measurement may be carried out on a test rig built in accordance with Figure 14 if the above requirements are met. The results of the measurements shall be expressed in such a way as to conform with relevant regulations and the requirements of this document. The test report shall include the following data:
test procedure;
thickness and nominal diameter of inlet and outlet pipes;
indication of the point at which the measured sound level is the highest;
the units of measurement used to express the results.
7.7.7.4.7
Test rig requirements
The requirements detailed in this sub-clause are mandatory only for type testing. The tests shall be carried out on a test rig built as specified in Figure 14 or in accordance with EN 60534-2-3 as appropriate. The nominal diameter of the pipework connecting the full bore valves and the flow rate regulating valves with the regulator shall not be smaller than the nominal diameter of the regulator and so chosen as to ensure that in all operating conditions during the tests the velocity of the gas does not exceed:
50 m/s for pressure ≥ 0,5 bar;
25 m/s for pressures < 0,5 bar.
The connections between the regulator and the test rig pipework shall be made using concentric reducers according to ISO 3419 or equivalent. The pressure tapping diameter b shown in Figure 13 shall be at least 3 mm and shall be no larger than 12 mm or one-tenth of the nominal pipe diameter, whichever is the lesser. The tapping shall be circular and its edge shall be clean and sharp or slightly rounded and free from burrs or other irregularities. Any suitable method of making a physical connection is acceptable provided the above recommendations are followed. However, fittings s hall not protrude inside the pipework.
55
EN 334:2005 (E)
In the event of unstable conditions due to volumetric flow rate variations consequent to the operation of the flow regulating valve 8 (see Figure 14), it is permissible to increase the length of the pipework connecting the flow regulating valve 8 (see Figure 14) to the regulator, or to provide for an additional volume by installing a parallel line or reservoir. The lock-up pressure tests shall always be carried out on a test rig in which the downstream pipework has the minimum specified length; for these tests an additional downstream volume is not permitted. The flow meter shall be installed in accordance with the instructions of the manufacturer. NOTE
For alternative test methods under the conditions of 7.7.7.4.1 see also Annex A.
Key 1
Minimum 2,5 b, recommended 5 b
Figure 13 — Recommended pressure tapping
56
EN 334:2005 (E)
Key 1
Shut-off device to prevent overpressure, if necessary
2
Inlet full bore valve
3
Inlet pressure indicator
4
Inlet temperature indicator
5
Regulator under test
6
Outlet pressure indicator
7
Outlet temperature indicator
8
Flow rate regulating valve
9
Flow meter
DN1 = nominal diameter of the upstream pipework connected to the regulator under test DN2 = nominal diameter of the downstream pipework connected to the regulator under test
Figure 14 — Test rig requirements
57
EN 334:2005 (E)
7.7.8 7.7.8.1
Final visual inspection After type test
Upon completion of the tests in 7.7.4 up to and including 7.7.7.4.5 and the test 7.7.7.4.6 when applicable, excluding the test in 7.7.7.3, the test samples shall be dismantled and inspected to verify the compliance with the requirements detailed in 5.4. 7.7.8.2
After routine tests and production surveillance
Upon completion of the routine tests the regulator shall be externally inspected. There shall be no visible evidence of damages and the markings shall comply with the applicable instructions.
8
Documentation
8.1 Documentation related to type test 8.1.1
Documentation required prior to type test
The following documentation shall be available at the tim e of carrying out the type test: a) photographs and/or leaflets; b) scheme and pertinent functional description; c)
technical data for the series of regulators and a list of performance data to be confirmed;
d) assembly drawing of the regulator; e) overall dimensional drawing; f)
nameplate drawing;
g) strength calculation or test report for all pressure containing parts; h) parts list with material description for all components; i)
manufacturing drawings of all pressure containing parts and critical internal components;
j)
installation, operation and maintenance manual.
8.1.2
Test report
On completion of the type test a report according to EN ISO/IEC 17025 shall be provided detailing the results of the tests carried out. If alternative methods under the provisions of 7.7.7.4.1 are used, they shall be described in detail in an appropriate section of the test report.
8.2 Documentation related to the routine tests 8.2.1
Documentation provided at the request of the customer
Inspection certificate and/or NDT certificate and/or material certificate in accordance with EN 10204 for pressure containing parts and for bolts, screws and studs if applicable.
58
EN 334:2005 (E)
8.2.2
Documentation provided with the regulator
Installation, operation and maintenance manual, in the language of the country of destination or in the languages accepted by the user, giving appropriate instructions on:
information on safe use of the connections detailed in 9.2;
safety requirements concerning commissioning and de-commissioning procedures;
safety requirements on filling/discharge of gas of/from the regulator;
periodical functional checks;
a statement of whether maintenance is possible and the relevant instructions;
data on the nameplate except serial number, year of manufacturing and specific set range;
hazards arising from misuse and particular features of the design when appropriate;
provisions, if any, for transport and handling;
how to trace the right spare parts;
storage requirements for spare parts,
a statement on installation according to the provisions of EN 12186/EN 12279;
a statement that the regulator does not require any protection against exceeding its allowable pressure when for the upstream pressure regulating station the maximum downstream incidental pressure (MIP d) is less than or equal to 1,1 x PS
shall be included with each regulator or shipment of regulators.
8.3 Documentation related to production surveillance in accordance with 7.6 8.3.1
Documentation to be available for production surveillance
For each series of regulators the manufacturer shall have available the following documentation:
type test report;
records of inspections satisfactorily passed during the manufacturing process.
8.3.2
Production surveillance report
The production surveillance report shall detail the results of all tests and verifications listed in 7.6.
59
EN 334:2005 (E)
9
Marking
9.1 General requirements Each regulator shall carry markings containing at least the following data:
manufacturer’s name and/or logo and/or registered trade-mark;
manufacturer’s town and country;
regulator type;
EN 334 (this document);
serial number;
year of manufacture;
nominal size DN;
flange ratings;
allowable pressure PS;
specific set range W ds;
operating temperature range (class 1 or class 2);
fail-safe modes (fail-open regulator or fail-close regulator);
valve seat diameter (only where different sizes are provided) or valve trim (for this term see EN 60534-1) or the flow coefficient if the previous data are not representative of the regulator flow rate;
maximum component operating pressure pmax of safeguarded chambers (for differential strength regulators only);
leakage class in accordance with EN 1349 if applicable;
where necessary, warning drawing attention to dangerous misuses;
additional marking in accordance with order specification.
The data shall be indicated using the symbols of this document. The flow direction shall be marked clearly and permanently on the body by an arrow. If a nameplate is used it shall be permanently legible and attached at a clearly visible place. The technical details listed above shall be repeated in the inspection certificate (see Annex B). The CE marking, where applicable, shall be accompanied by the manufacturer’s name and/or logo and/or registered trade-mark, regulator type, serial number, year of manufacture, allowable pressure, specific set range and operating temperature range.
60
